.App {
  text-align: center;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-header {
  background-color: #28a745;
  padding: 20px;
  color: white;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.app-header h1 {
  margin: 0;
  font-size: 24px;
}

.app-header nav ul {
  list-style-type: none;
  padding: 0;
  margin: 10px 0 0;
  display: flex;
  justify-content: center;
  gap: 20px;
}

.app-header nav ul li a {
  color: white;
  text-decoration: none;
  padding: 8px 16px;
  border-radius: 4px;
  transition: background-color 0.3s;
}

.app-header nav ul li a:hover {
  background-color: rgba(255, 255, 255, 0.2);
}

.app-main {
  flex: 1;
  padding: 20px;
  background-color: #f8f9fa;
  display: flex;
  flex-direction: column;
}

.app-footer {
  background-color: #343a40;
  color: white;
  padding: 20px;
  text-align: center;
}

/* 页面标题 */
.page-title {
  color: #333;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid #28a745;
}